Expansion boring-tool.



N0. 757,494. Y PATENTED APR. 19, 1904.

` W. POHLMAN.

EXPANSION vBORING TOOL.

APPLICATION FILED FEB. 19, 1903.

NGL IODEL.

'El j UNITED STATES Patented April 19,4 A1904:.

VILLIAM POHLMAN, OF MIDDLETOVVN, NFNV YORK.

EXPANSION BORING-Tool..

SPECIFICATION forming' part of Letters Patent No. 757,494, dated .April19, 1904. Application led February 1 9, 1903. SeriallNo. 144,155. (Nomodel.)

To all whom it may concern:

Be it known that I, 1WILLIAM POHLMAN, a citizen of the United States,residing at Middletown, in the county of Orange and State of New York,have invented certain new and useful Improvements in ExpansionBoring-Tools, of which the following is a full, clear, and exactdescription, such as will enable those skilled in the art to make anduse the same, reference being had to the accompanyingdrawings, formingpart of this speci'cation, and whereinv Figure l is a general` View ofboring-tool; Fig. 2, asection of boring-tool through'its center; Fig. 3,a view of boring-tool from lower end; Fig. 4c, a lview of detachedtool-holders, showing plan, side, and end. Fig. 5 showsa position ofwedges when annular ring is below the end of the wedges.

y My invention relates to that class of boringtools wherein thecutting-tools aremoved laterally from and to the center to suit anyintermediate diameters and graduated in such a manner that the diameterof the cutting edges can readily be increased or decreased a knownamount (such as one-thousandth part of an inch) by an unskilled workmanwithout the aid4 of any measuring-tools, each of the cutters being moveduniversally to the same radius from the center. The number of cutters1used is adapted to the size of the boringtoo Referring to Figs. 1 and 2,the shank of the boring-tool is shown with a taper end for use in thespindle of a boring-mill or drilling-machine; but a square shank can besubstituted when it is desired to operate` the tool as a reamer. Thebody A is formed of one piece with the shank S, the upper part of itsouter diameter being furnished with a screw-thread A2, (eight threadsper inch being used in the present case for convenience of ligures, asshown hereinafter.) vThe screw-threads extend down body A nearly thelength of jamnut R. Laterally through body A and near its lower end arefour square openings A', in which move the tool-holders D.Longitudinally. of the body A are four recesses or grooves C. ,in whichslide the adjusting-wedges C. These adjusting-wedges, which freely Dwould be moved toward the center, thus move vertically in theirrespective recesses, are provided with screw-threads on their outersurfaces, the diameter and pitch of thread corresponding with those onthe outside of the body A, and their lower ends are beveled to an angleof forty-five degrees, declninginward and forming the wedges C3. Anannular ring B with threads on its inside is screwed on the bodyAuntilitis clear of the threads of same, where it then engages thethreads of the vertical wedges C. The lower edge of annular ring B isalso beveled at an angle of forty-tive degrees on the inside lower edge,forming wedge B'.v On the outside'of annular-ring Bare holes B2, inwhich to insert the prongs of a Spanner- Wrench for adjusting thetool-holders D. To securely hold all parts in their positions whenadjusted,` a jam nut R is provided, having similar holes in its outersurface in which to insert wrench, as in the annularring. In theLlateral openings A are placed tool-holders D, each having a A-shapedprojectionD on its upper surface and on which impinges the beveled edgesof the vertical wedges C3 and annular ring B' when it is screwed downuntil their lower edges are even with each other. If the lower edge ofAannular ring B should be screwed below the edge of the wedges C3 andsecured by jam-nut R, the tool-holders decreasing the diameter of thecutting edges of tools L, and to increase the diameter of cutting edgesthe vertical wedges C should be lowest, as the beveled edges beingthrust downward on the projection D would force the tool-holders outwarduntil the opposite side of projection D' would come in contact with thebevel on the annular ring, and as all the tool-holders are on the sameplane they are all moved laterally in unison. The tools L are pieces ofsquare steel cut to a proper length and with suitable cutting edges aresecured in tool-holders D by a small set-screw D2. For setting the toolsL a gage is used to insure each projecting a uniform distance .from theface of tool-holder D. The outside the vertical wedges C makes adifference of 100 one-eighth inch in their relative positions, (therebeing eight threads per inch,) and the angle of the projections DlbeingIoity-five degrees each of tool-holders are moved onehalf of thisdistance laterally, or one-sixteenth inch each. If moved only onegraduation, the distance the tools moved would be only one hundred andtwenty-fifth of one-eighth inch, or one one-thousandth of an inch. A xedpointer P is secured to the body A, at which point is indicated theamount of adjustment.

To assemble the different parts of the boring-tool, the tool-holders Dare placed in the lateral openings A until the inside edges of theprojections Dl touch the body A. Place the vertical wedges C in therecesses C', with their lower edges resting on the projections D. Screwthe annular ring B over the top part of body A and continue down thethreads of the vertical wedges C'until its lower beveled edge also restson the bevel of projection 'D' on the tool-holders. The jam-nut R isthen screwed on the body A until its lower edge impinges on the top ofannular ring B, forcing it downward on the projections D' and securingthem all in the same radius from center of tool. A hole F is shown boredupward in the center of tool and tapped, so that a center can readily beapplied for adjusting work to the center of the boring-cutters oradjusting the center of' platen on a drill-press.

One of the uses to which this boring-tool can be applied is the boringof car-wheels, where a quantity may all be bored to same size withoutchanging the tool, and if slight Variations in size are necessary whenfitting wheels on second-hand axles it can readily be done bycaliperingthe wheel lit of axle and measuring same with Vernier-caliperand then measure the last wheel bored. The difference is made by simplyloosening the jam-nut R and setting the proper graduation-marks on theannular ring B opposite to the pointer` and then securing the jam-nutRagain in its place.

In boring holes where the bottom is larger in size that the top thistool can be used, as the diameter can be changed without withdrawng thecutting edges'from the hole being bore Having described my invention, Iclaim as v ed in the recesses and having threads on one side, a ringthreaded on the wedges, tool-holders in the lateral openings and meanson the tool-holders engaged by the wedges and ring whereby the operationof the wedges and ring adjusts the tool-holders and means for retainingthe ring in its adjusted position.

2. In an expansion boring-tool, a body having a transverse toolway, atool-holder in said way having a projection, wedges arranged to bearupon opposite sides of said projection and relatively movable to projector retract the tool-holder and means for holding the wedges in adjustedpositions.

3. An expansion boring-tool having abody vprovided with lateralopenings, tool-holders seated in the lateral openings, and havingprojections with oppositely-disposed cammingsurfaces, a ring on the bodyfrictionally engaging the projections 0I' the tool-holders, memberscoacting with the ring on the projections of the tool-holders, means forconnecting the ring and members so that movement of the ringcommunicates movement to justed position.

5. An expansion boring-toolhavinga body provided with lateral openingsand a pointer,

tool-holders having projections with cammingsurfaces, in the openings, aring and wedges coacting oppositely on the camming-surfaces, means forholding the ring in adjusted position, the said ring having graduateddivisions under the pointer and cooperating means on the ring and wedgesfor holding them in relative adjustment.

In testimony whereof I havev signed my name to this specication in thepresence 0I' two subscribing witnesses.

WILLIAM POHLMAN.

Witnesses:

WILLIS H. DAVIS, y IRVING G. DowNs.

IOO

